1. Field of the Invention
The present invention relates to a portable light source apparatus which can be brought into work sites.
2. Related Background Art
Conventionally known as a technique in such a field is Japanese Patent Application Laid-Open No. HEI 8-329732. The light source apparatus disclosed in this publication has means for cooling a deuterium lamp. Namely, the deuterium amp is accommodated in a light source block, whereas a vent hole formed in the light source block and a cooling fan are connected to each other by an air duct, so that cooling winds sent out from the cooling fan pass through the light source block, thereby indirectly cooling the deuterium lamp.
However, though the above-mentioned conventional light source apparatus is contrived such that the deuterium lamp is cooled with cooling winds, the deuterium lamp does not operate stably when simply cooled and may not achieve a desirable stability of output when cooled in excess. This results from the structure of the deuterium lamp, which maintains a low pressure state of {fraction (1/100)} atm or so therewithin, thus having a characteristic which is quite easily affected by temperature changes in the outside air. Conventionally, while the deuterium lamp is accommodated in the light source block, the light source block is utilized so as to be directly in contact with the outside air, whereby the deuterium lamp is quite susceptible to changes in the outside temperature in work sites, thus leaving a problem that it is difficult for the deuterium lamp to attain a stable output characteristic. Japanese Patent Application Laid-Open No. HEI 8-233659 discloses means for directly cooling a deuterium lamp while in a state where the deuterium lamp is accommodated in a light source chamber.
In order to overcome the problems mentioned above, it is an object of the present invention to provide a portable light source apparatus which, in particular, is less likely to be affected by temperature changes in the outside air, so as to attain a very high stability in output.
This portable light source apparatus comprises a lamp box, secured within a housing, accommodating a deuterium lamp for generating a predetermined wavelength of light, and having a light exit opening for letting out the light emitted from the deuterium lamp; a power unit, secured within the housing, for driving the deuterium lamp; and a cooling fan, secured to the housing, for generating a forcible air flow within the housing; wherein the lamp box is formed with a lamp accommodating space having an opening at an upper part thereof; and wherein the deuterium lamp is accommodated in the lamp accommodating space while orienting a stem side thereof upward.
This portable light source apparatus is an apparatus for lighting/blinking a deuterium lamp. The deuterium lamp does not operate stably when simply cooled. This is because of the fact that the deuterium lamp maintains a low pressure state (e.g., about {fraction (1/100)} atm) therewithin, there by exhibiting an output characteristic which is quite susceptible to temperature changes. Therefore, such a deuterium lamp is accommodated in a lamp box and, at the same time, in a housing in order for the influence of temperature changes in the outside air to become very small. Namely, the deuterium lamp, which is susceptible to changes in temperature, is enveloped not only by the lamp box but also by the housing, thereby being accommodated in a double shield structure. As a result, the temperature change of the housing, which is the most likely to be affected by the outside air, is harder to be transmitted to the deuterium lamp, whereby the latter can be utilized without taking account of the changes in weather during outdoor operations or influences of air conditioners and the like during indoor operations. Further, in the present invention, the deuterium lamp can be inserted into and removed from the lamp box from thereabove, so that operations of replacing the lamp become easier even when the housing is made compact, whereby the light source apparatus can be carried easier outdoors and in the field.
Preferably, in the portable light source apparatus, the housing is provided with a detachable upper lid at a position facing to the opening of the lamp box. In this case, since the upper lid is employed, the housing can be opened only at the time of lamp replacing operations. Since the lamp replacing operations can be carried out while the lamp box is looked into from thereabove when the upper lid is removed, the lamp, which is easy to break, can be replaced safely.
Preferably, in the portable light source apparatus, a flange part, made of a metal, projecting in a direction perpendicular to a tubular axis is provided on the stem side of the deuterium lamp, whereas the deuterium lamp is held within the lamp accommodating space of the lamp box while the flange part abuts against the upper end of the lamp box. In this case, the deuterium lamp can easily be accommodated in the lamp box while in a suspended state. Also, the operations for replacing the lamp can be carried out while the flange part is picked up by fingers, so that no fingers come into contact with the glass part, whereby the luminance can be prevented from becoming uneven due to smudges such as fingerprints. Also, since the lamp box and the flange part of the deuterium lamp abut against each other, the flange part provides an appropriate lid for the lamp accommodating space, whereby cooling winds can appropriately be prevented from entering the lamp accommodating space.